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Salamanders in the family Plethodontidae exhibit a unique tail-straddle walk during courtship that can include the use of sexually dimorphic mental and caudal courtship glands. This study presents novel histological and fine structure data on mental glands and caudal courtship glands in Plethodon mississippi, Desmognathus conanti and Eurycea quadridigitata using both light microscopy and scanning electron microscopy. This study represents the first use of scanning electron microscopy to observe these glands. Both mental and caudal courtship glands were observed to vary seasonally in gland diameter and histology according to the breeding season of each species. Morphological variation was observed across the three species studied in both clustering and relative size of the glands compared to neighbouring mucous and granular glands. Hypertrophied mental glands are larger than mucous or granular glands in all species, but relationships among caudal courtship glands and other skin glands vary among species. In E. quadridigitata, active caudal courtship glands are larger than mucous and granular glands, but in D. conanti, caudal courtship glands are similar in size to granular glands and larger than mucous glands. In P. mississippi, caudal courtship glands are scattered among significantly larger granular glands and are similar in size to mucous glands. [ABSTRACT FROM AUTHOR]

Mental glands are sexually dimorphic glands found in the skin of the submandibular region in males of many species in the salamander family Plethodontidae. These glands have been demonstrated to secrete pheromones that increase female receptivity to courtship and mating. A number of studies exist on the morphology of mental glands at the light microscopy level, but ultrastructural studies on the glands exist for only two species, Eurycea quadridigitata and Hydromantes italicus. In this study, ultrastructure of the mental gland is described from seasonal samples of the eastern North American plethodontid Plethodon cinereus. The mental glands are most hypertrophied in males examined in mating condition (i.e. sperm in their Wolffian ducts) in October and April. In these specimens, 6- to 8-μm electron-dense secretory vacuoles are found in the apical cytoplasm (October) or throughout the entire epithelial cells (April). Mental glands from June and August contain only condensing vacuoles, and the cytoplasm is otherwise packed with stacks of rough endoplasmic reticulum. The ultrastructure of the mental gland of P. cinereus agrees with earlier descriptions for E. quadridigitata and H. italicus. Two other sexually dimorphic skin glands, the caudal courtship gland and the cloacal vent gland, were previously examined from males in this sample of P. cinereus. Although all three glands show similarities in histology and histochemistry at the light microscopy level, they are dissimilar in ultrastructure. Whereas the secretory vacuoles of mental glands are uniformly electron dense, those of caudal courtship glands are smaller (1.2-1.5 μm), oblong and biphasic, and vent glands have spherical biphasic secretory vacuoles (1.8-2.1 μm). This indicates a difference in secretory product and function for the three glands and needs further investigation. Whether other plethodontids show similar variation among sexually dimorphic glands is another topic for future research. [ABSTRACT FROM AUTHOR]

Over the past decade, studies on reproductive morphology in the Squamata (snakes and lizards) have expanded tremendously. With the accumulation of these studies and revisions of the terminology based on structural similarities and differences, it is imperative to review the work on tuataras to determine whether the structural organization fits the revised terminology of vertebrates. We investigated the morphology of the male reproductive system in the Tuatara, Sphenodon punctatus ( Rhynchocephalia), the sister taxon to the Squamata. Previous studies on the Tuatara used a nomenclature for the testicular ducts different from the current terminology for amniotes. The reproductive system in the Tuatara is consistent with reports in the Squamata. Two rete testis tubules exit the testis within a connective tissue sheath similar to that shown in other squamate species and the protherian Echidna. Each rete testis divides into multiple ductuli efferentes that fuse with the epididymis. The epididymis transitions into the ductus deferens where the sperm become more concentrated into spherical bundles. The ductus deferens enters the cloacal urodeum separately from the ureter. An ampulla ureter or ampulla urogenital papilla was not observed, which differs from previous studies of lepidosaurians. Furthermore, a sexual segment of the kidney ( SSK) was not observed, consistent with previous studies on the Tuatara. [ABSTRACT FROM AUTHOR]

The anatomy and histology of the cloaca and spermatheca of 13 female smooth newts (Triturus vulgaris) were studied by light microscopy. The cloaca consists of a short, anterior tube (which receives the oviducts). which opens into a larger. more posterior chamber. The spermatheca, which is the only gland in the cloaca, consists of a mass of exocrine, acinar tubules which empty individually and dorsolaterally into the posterior part of the cloacal tube and all but the most posterior part of the cloacal chamber. Stored sperm are most abundant in the spermathecal tubules during the peak of the breeding season (in May and June); during their period of storage, the sperm do not appear to make intimate contact with the epithelial cells lining the spermathecal tubules. Long- term storage of viable sperm from one breeding season to the next is probably absent in the smooth newt. Sperm storage by and multiple insemination of females both occur in this species and are necessary preconditions for competition between the sperm of different males for the fertilization of eggs. However, sperm competition has not been demonstrated in the smooth newt. [ABSTRACT FROM AUTHOR]